Field of the Invention
The present invention relates to pneumatic tires, and in particular relates to a pneumatic tire having excellent performance on snow and steering stability on dry road surfaces.
Description of the Related Art
Japanese Unexamined Patent Application Publication No. 2013-216118 has proposed a pneumatic tire which may have excellent snow performance and uneven wear resistance. The pneumatic tire disclosed in the publication includes a block which is surrounded by a groove and which includes a main portion having a ground contact surface and a step-shaped auxiliary portion protruding laterally from the main portion and terminating in the groove.
Unfortunately, in the above mentioned pneumatic tire, when the step-shaped auxiliary portion increases in length, the snow performance tends to be deteriorated owing to reduction of groove volume despite the fact that the steering stability on dry road surfaces improves. Furthermore, in the above mentioned pneumatic tire, when the step-shaped auxiliary portion decreases in length, the steering stability on dry surfaces tends to be deteriorated owing to reduction in rigidity of the block despite the fact that the snow performance improves.